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Thread: engine head parts-cast iron recommendation

  1. #31
    Join Date
    Dec 2016
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    Helsinki, Finland, Europe
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    Quote Originally Posted by mtraven View Post
    While I really appreciate the help in finding replacements and will pursue those, I am a bit thrown by the discouragement to make them myself. This is a machinist forum right, we make stuff, no? I have found a plug that would probably work with some machining, though that machining is harder to do now that its cut down to size and 3 of them will cost be $200 bucks & a couple of weeks...then I still have to machine them.... I can probably machine from scratch them by tuesday for like $20 in materials (still undecided). Also, the originals were the main point of failure & caused a lot of damage to my engine, so I am not dying to put those in.

    I am leaning towards stainless steel for the replacements (303 or 17-4) and would like to hear some opinions on material selection


    ps did anyone look at the photos I posted of the prototype replacement?
    If you can source chuck of Nimonic 80, Hastelloy or Inconel go ahead and make your own. IMO bigger problem than nasty machinability is the availability for home shop guy..

  2. #32
    Join Date
    Nov 2011
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    Chicago, IL
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    Quote Originally Posted by MattiJ View Post
    If you can source chuck of Nimonic 80, Hastelloy or Inconel go ahead and make your own. IMO bigger problem than nasty machinability is the availability for home shop guy..
    hastelloy & inconel are available from mcMaster-carr, though i'd be looking at 4-5x the cost of 17-4 ss.

    in trying to determine what the existing one is made of, I scrubbed in with every nasty solvent I could find, left it wet with water to see if it would rust....it did not...at all, not even the spot I hit with a file to test hardness(its not very hard at all). It also has a yellow patina that I have seen on heated SS but that I don't usually see on carbon steel without any rust. So I think I can rule out cast iron & carbon steel on account of the rust(lack there off). I think it was probably a SS, but I'm not sure if there are steel alloys, outside the SS class, that do no rust, for example, can inconel rust? Its high chromium & nickle and very little iron content makes me think it would not rust. hence the OEM part could have been that? One more detail, it is strongly attracted to a magnet.

    so summarize, the mystery metal is:

    -strongly attracted to a mag
    -does not rust
    -file bites in easily


    whats your guess?
    "it is no measure of mental health to be well adjusted to a profoundly sick society." -- krishnamurti
    "look deep into nature, and then you will understand everything better." -- albert einstien
    "any intelligent fool can make things bigger and more complex...It takes a touch of genius - and a lot of courage to move in the opposite direction."

  3. #33
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    Dec 2007
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    South Wales
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    Ferritic stainless steel
    Mark

  4. #34
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    Jan 2016
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    Midlands UK
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    May be what we in the UK call 400 series stainless which is a ferritic. Try a search for 420 stainless, I used to buy this from "Cru-Steel" an American company with a UK outlet. I would love to see a good picture of the inside of the part you intend to make, I was put off attempting to make Land Rover ones some years ago due to the cast spikes on the inner surface. Maybe the ones you are doing don't have the spikes ?

  5. #35
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    Nov 2007
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    Woodinville, WA
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    17-4 is also magnetic. I question what the continuous heat cycling will do to any of the ferric or precipitation hardening stainless. Were you thinking of heat treating it? If so.. to what?.

    One reason it many have been listed as "non serviceable" is that they could have been made oversize and cooled in liquid Nitrogen for a shrink fit. Nothing you can't do at home with a little pre-planning.

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